Instrument for the automatic determination of moisture in paper or textiles



Sept. '30 1924. 1,509,869

A. -R. HARVEY INSTRUMENT FOR THE AUTOMATIC DETERMINATION OF MOISTURE IN PAPER OR TEXTILES Filed JLly 11, 1923 2 Sheets-Sheet l 4-0.6.NA/A/S Juucnro-t A. R. HARVEY INSTRUMENT FOR THE AUTOMATIC DETERMINATION OF MOISTURE IN PAPER OR TEXTILES Sept. 30 1924.

Filed July 11 1923 2 Sheets-Shae. 2

3n uc'n fo'c Hart/f 25 ment or conditions.

Patented Sept. 30,- 1924.

1 UNITED STATES PATENT OFFICE.

ARTHUR R. HARVEY, F MIDDLETOWN, OHIO.

I INSTRUMENT FOR THE AUTOMATIC DETERMINATION OF MOISTURE IN PAPER OB l TEXTILES;

Application filed July 11,

To all whom it may concern:

Be it known that ARTHURR; HARVEY, citizen of the United States, residing at Middletown, in the county of Butler and State 5 of Ohio, has invented certain new and useful Improvements in Instruments for the Automatic Determination of Moisture in Paper or Textiles, of which the following is a specification.

The purpose of the present invention is to provide improved means to indicate, and if desired, to record graphically, the per cent 'of moisture contained in paper while it is. in the process of manufacture. The instrument is designed to be placed in such a position as to determine the moisture con: tent of the paper before its passage to the drier, or at any subsequent timein the manufacture thereof before it is cut into sheets.

.20 This instrument might also be used for controlpurposes, in regulating the quantityof steam admitted to the driers, the quantity of air blowif or otherwise admitted to the driers, or for controlling other drying equip- The device depends upon heat capacity for its principle of operation.

To my knowledge, there is at present no instrument which gives this result and which 3 depends upon specific heat for its principle. At the present time, moisture content is found by tearing out a sample of the paper and weighing it before and after-driving off its moisture by heat. This involves ex- 3 (often breaking down the paper web in attempt to extraeta sample), vand what the most important, a delay of appro'ziimately one hour before the resultis 0b 40 water is dried out. -This type of machine is however, only applicableto the dry end pensive labor, a waste of materials and time tained. An accurate and instantaneous re-":. sult is therefore of great value in produc ng;

attempt "to control drying conditions cor- 1923. Serial no.'e5o, s1o.

accordingly an object of the invention to .provide a device which may be so placed ahead of the drier. v The last named type of machine now in use is objectionable, also, because other factors influence the tension of the paper beside the moisture content thereof.

A further device which has been attempted, depends upon the electrical conductivity of paper to control the drying apparatus. 'An objection to this method is that the conductivity Will be affected by the temperature of the paper and also by the electrolytes in solution in the water contained, it being noted that the water usually contains alum and other salts in varying proportions. The present invention, working upon the principle of heat capacity, will be effective because the heat capacity will not be appreciably effectedby any salt dissolved in the water, and is not a function of the initial temperature. The instrument constituting the present invention, is therefore one'which possesses inherent advantages not found in prior instruments of this kind.

Other objects will appear as the natureof the invention is better understood, and the same consists in the movel form, com:

bination and arrangement of parts herein after more fully described, shown in the accompanying drawings and claimed.

' In the drawings, wherein a preferred embodiment of the invention is shown, and

wherein like reference characters indicate corresponding parts throughout the several views, y l 31 Figure l is a side elevational view of an instrument constructed in accordance with the present invention,

Figure 2 is afront elevational view of the device shown in Figure l, partly broken away to illustrate details of the invention, Figure 3 shows a wiring diagram for the heating roll, and

Figure 4 showsjawiring diagram for the temperature measurement roll. 4

The present device consists essentially of two principal parts, a heating element anda temperature measurement element, the heatin'g element preferably having a constant and known quantity of heat supplied therethrough to the paper, and the temperature measuring element preferably respond ng to the temperature rise due to the heat input. The heating element preferably consists of a roll over which the paper is made to pass, and is preferably heated by electricity so as to provide for accurate heat control, although other means of heating the roll could be utilized, such as steam, hot water, etc. When heated electrically, the roll contains or consists of resistance units so connected to the main that a constant power supply results.

The temperature lneasurin device consists of an arrangement of t ermo-couples and rolls over which the paper passes, and associated with means which indicates the temperature rise of the paper after passing over the heating roll.

Referring to the drawings in detail, the roll designated by the reference character 5 represents the heating element, and as shown, has a resistance wire 6 coiled about the inside thereof in the form of a spirah This resistances is insulated as at 7 from the roll proper by a thin strip of asbestos, and the latter is securely fastened to the internal face of the roll. The ends of the roll may be protected from heat loss by being constructed with a suitable heat insulation such as asbestos or other suitable material, these ends being indicated by the reference numeral 8. The leads 9 from the heating units are brought out through the hollow shaft 10 of the roll 5 and are adapted to be connected with the source of current supply by means of slip rings 11 associated with suitable brushes 12. The heating circuit, as shown in Figure 3, must contain the heating element 6, a watt-meter 13, and a suitable rheostat 14 for controlling the input. The roll itself is preferably constructd of thin metal tubing of the proper'diameter.

The means for obtaining the temperature difference includes rolls 15 and 16 arranged above and at opposite sides of the heating roll 5 and containing thermo-couple junctions 17, the electrical connections to which are made through slip rings 18 to a millivoltmeter or potentiometer 19, as shown in Fignrr This millivoltmeter or potentiometer is prferably calibrated to read directly in terms of per cent moisture contained in the paper, and the principle involved in this calibration may be mathematically shown as follows:

' (T2 T1) wX v l' pX r) :Q'

where T =temperature of paper after heating T,-'-temperature of paper before heating W =weight of water contained in the paper plus the weight of dissolved substances S =specific heat of above W ==weight of bone-dry paper passing over the instrument in unit time s specific heat of above Q.=Quantity of heat supplied in unit time.

For a given rate of production on the paper machine, all the above factors will be known except \V (assuming S =1). The quantity 1V can therefore be calculated from which the percentage moisture in the paper can be found thus:

Ww i W x 100 per cent moisture.

The rolls 15 and 16 are preferably sup ported in such a way that they may be thrown away from the heating roll 5 to provide the necessary clearance for threading the paper about the rolls so as to facilitate starting up of the machine initially, or after a break in the web lV- whose moisture content is to be found. As shown in Figures 1 and 2, suitable mounting brackets 20 are provided in which the shaft 10 of the heating roll 5 is journaled, while arms 21 have the shafts of the rollers 15 and 16 journaled therein at the upper ends thereof. These arms 21 are preferably pivotally supported by rock shafts 22 having means generally denoted by the numeral 23 for adjusting the arms 21 in any desired swung position toward or away from the roll 5. One of the rolls 16 is shown by dotted lines in Figure 1 as swung in a lowered inoperative position to illustrate this construction.

It is obvious that a suitable scriber may be carried by the pointer of the millivoltmeter or potentiometer 19 and associated with a recording sheet, if a graphic record is desired.

When the heating and temperature measuring elements are combined respectively in single rolls, the resulting moisture content indication will be the mean content across the sheet of paper. However, it is often desirable that the moisture content be known at several different points, and this can be done by breaking up the rolls in several sections arranged end to end and having independent indicating means. In this way, the moisture content will be indicated for the front, back and middle of the web.

An instrument is thus provided whose basic principle depends upon the relationship between the moisture content of the paper and the heat capacity thereof. it being noted that in the device disclosed in the present drawing, a constant rate of heat will be supplied to the roll 5 as the web W moves therearound, and as the temperature indicator 19 is under the influence of the rolls 15 and 16, respectively subjected to the heat of the paper before and after being heated by the roll 5, said indicator will show accurately the moisture content of the paper when calibrated as above described.

measurement made o f'the heat necessary to cause this temperature "rise. So'far as the instruments and theirconnections go, the

.two devices would differ greatly, but both would in reality be measuring the heat capacity. It is therefore to be understood that various changes may bemade in the construction shown without departing from the spirit and scope of the invention as claimed.

From the foregoingdescription it is believed that the construction and operation of the invention as well as the \advantages thereof will be readily understood and appreciated by those skilled in the art.

What I claim as new is: a

1. In an instrument for the automatic determination of moisture con-tent in a web while moving during its course of manufacture, means for supplying heat to said web,

means sensitive tothe heat of the web before and means sensitive to the heat of the web after being heated by said heating means, and an indicator controlled by said heat sensitive means for indicating the moisture content of said web.

2. An instrument for the automatic determination of moisture in a web while moving during its course of manufacture, comprising a heating roll about which the web is adapted to be moved, a pair of rolls about which the web is adapted to respectively pass before and after passing around the heating roll, means carried by said second named rolls sensitive to the heat of the web, indicating means and electrical connections with the indicating means and said last named sensitive means for indicating the moisture content of the web.

3. An instrument for the automatic determination of moisture in a web while moving during its course of manufacture, comprlsing a heating roll about which the web is adapted to be moved, a pair of rolls about which the web is adapted to respectively pass before and after passing around the heating roll, means carried by said second named rolls sensitive to the heat of the paper, and indicating means in electrical connection with said last named sensitive means forindicatin the moisture content of the web, said pair of rollers being mounted for swinging movement toward and away from each other and from the heating roll for facilitating threading of the web around said rollers.

4. An instrument for the automatic determination of moisture in a web compris mg means to supply heat to sald web, means sensitiveto theheat of said web before and means sensitive to the heat of the web after being subjected to said heating means, and

an indicator actuated by said last named heat sensitive means.

5. In combination, an indicator, an operatmg means therefor comprising apair of rotatable elements, mounted in spaced relation and adaptedfor contact and rotation with a movable web, heat responsive means mounted insaid elements for contact with said web, responsive to variatlons 1n the tem-' perature of the web, and means operatlvely said indicator adapted for operating said indicator to register the percentage of moisture in the web.

6. In combination, an indicator, and an instrument for operating said indicator comconnectingthe heat responsive means with prising a base member, a pair of spaced swinging frames hingedly mounted on said base member, rolls rotatably mounted in said frames adapted for contact with a movable web, thermo-couples mounted in said rolls for contact with the web, and connections between the thermo-couple' and the. indicator for operating said indicator for registering the percenta e of moisture in the web.

7. In com ination, an indicator and operating means therefor including a pair of spaced rotatable elements ada ted to contact and rotate with a movable web, supporting means for said elements, means re-' sponsive to the heat of the web mounted in said rotatative elements for contact with said web, and connections with said means and said indicator adapted to operate said indicator to register the percentage of moisture in the web.

8. A device for indicating the percentage of moisture in a web comprisin an indicator and controlling means there or having a pair of heat responsive elements mounted for contact with said web at spaced intervals and operated by the heat of said web at the points of contact of the elements therewith and connections between the indicator and elements for operating said indicator according to the heat in the web on said elements.

9. A device of the class described comprising an indicator, means for supplying a predetermined known quantity of heat to a portion of a movable web and means contacting with the web at spaced intervals, said spaced points of contact being adapted to engage the web at both the heated portion and an unheated portion thereof, and connections between the last mentioned means and the indicator for operating the indicator to register the percentage of moisture in said web. 1

10. A device of the class described comprising means for supplying heat to a portion of a movable web, means contacting with the web at spaced intervals adapted to engage a portion of the web at the point of engagement by said heat supplying means and an unheated portion thereof spaced from the heating means, an indicator controlled by said last mentioned means, said last mentioned means being sensitive to the heat and o 11. A device of the class described comprising means for supplying a predetermined amount of heat to a portion ofa web,

heat, sensitive means mounted for contact with a portion of the web heated by the first mentioned means and an unheated portion thereof, and an indicator and connections 15 between the indicator and heat sensitive means adapted to operate and control the indicator for registering the percentage of moisture in said web.

In testimony whereof I aflix my signature.

ARTHUR R. HARVEY. 

